The increased use of composite materials in various high performance applications has raised the demand for materials having improved performance characteristics. Improved performance characteristics can include mechanical properties such as, for example, improved tensile strength, stress/strain performance, impact resistance, Young's Modulus, shear strength, shear modulus, toughness, compression strength, and/or compression modulus. To enhance these properties and others, composite materials contain a filler, typically a fiber material, that conveys its characteristics to the bulk composite matrix (e.g., a polymer matrix, a metal matrix, a ceramic matrix, or a glass matrix), thereby imparting enhanced properties to the composite material as a whole.
The fiber material of a fiber-containing composite material can be particularly critical for imparting enhanced properties to the composite material. Since the properties of the fiber material are imparted to the composite material as a whole, enhancement of the mechanical properties of the fiber material can result in improved properties of the bulk composite material. Conventional microscale fiber materials typically exhibit tensile strengths ranging from about 800 ksi to about 900 ksi. A number of enhanced fiber materials have improved upon these values, but many of these enhanced fiber materials are not amenable to large scale production due to their inability to produce defect-free continuous fibers. Further, many of these enhanced fiber materials are quite costly.
Nanoscale reinforcement of composite materials is another strategy that has been pursued to improve the mechanical properties of composite materials. Nanoscale reinforcement has most often been performed with carbon nanotubes, which have exceptionally high tensile strengths. Multi-wall carbon nanotubes, for example, have the highest tensile strength of any material yet measured, with a tensile strength of approximately 63 GPa having been achieved. Moreover, theoretical calculations have predicted a possible tensile strength of up to about 300 GPa for certain carbon nanotubes. Composite material reinforcement strategies utilizing carbon nanotubes have typically involved the dispersion of carbon nanotubes in the composite matrix as a separate and distinct component from the fiber material. Most of these composite materials have attempted to align the carbon nanotubes in a substantially parallel arrangement relative to one another. In spite of the promise offered by carbon nanotubes as a nanoscale reinforcement material, complex issues can be encountered when incorporating carbon nanotubes in a composite matrix. These issues can include, for example, increased matrix viscosity upon carbon nanotube loading and uncertain carbon nanotube orientation and gradient control.
In view of the foregoing, a scalable, high quality, and cost effective strategy for preparing enhanced fiber materials would be of substantial benefit in the art. In a non-limiting example, such enhanced fiber materials can be used in the preparation of high performance composite materials. The present disclosure satisfies these needs and provides related advantages as well.